SQLite db not writable - ios

Question

I have a pre-populated SQLite db created with the Firefox SQLite Manager plugin.
I have included the DB to my project, added to the target and copied into destination group's folder. Then I created this function to copy the DB in the Documents folder:
-(void) createEditableDatabase{
BOOL success;
NSFileManager *fileManager = [NSFileManager defaultManager];
NSError *error;
NSString *writableDB = [[NSHomeDirectory() stringByAppendingPathComponent:#"Documents"] stringByAppendingPathComponent:#"DB.sqlite"];
success = [fileManager fileExistsAtPath:writableDB];
if (success){
return;
}
NSString *defaultPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:#"DB.sqlite"];
error = nil;
success = [fileManager copyItemAtPath:defaultPath toPath:writableDB error:&error];
if (!success){
NSAssert1(0, #"Failed to create writable database file:%#", [error localizedDescription]);
}
if (error){
NSLog(#"error = %#", [error localizedDescription]);
}
}
then I call this function in -(void)viewDidLoad and if I check in the simulator folder, a copy of the DB appears once I start the app.
The app runs fine, I can populate a UICollectionView with the data retrieved from the DB.
Then, when I try to insert some data, I receive no error but no data is added to the DB.
This is the code I use in MyViewController.h :
#property (nonatomic) NSString *DBPath;
#property (nonatomic) sqlite3 *myAppSQLITE;
This is the code I use in MyViewController.m :
-(IBAction)done:(id)sender{
DBPath = [[NSHomeDirectory() stringByAppendingPathComponent:#"Documents"] stringByAppendingPathComponent:#"DB.sqlite"];
const char *dbpath = [DBPath UTF8String];
sqlite3_stmt *statement;
if (sqlite3_open(dbpath, &myAppSQLITE) == SQLITE_OK){
NSString *querySQL = [NSString stringWithFormat:#"INSERT INTO myTable (name, age) VALUES('frank',30);"];
const char *query_stmt = [querySQL UTF8String];
if (sqlite3_prepare_v2(myAppSQLITE, query_stmt, -1, &statement, NULL) == SQLITE_OK){
sqlite3_finalize(statement);
}
sqlite3_close(myAppSQLITE);
}
}
I receive no error/warning but the data is never updated, even with a [self.collectionView reloadData];. If I run the same query with SQLite Manager in Firefox, everything works fine. If i open the DB inside the Simulator Documents folder with SQLite Manager, the DB is intact with no updated data. I have the same result running the app with my iPad.
How can I solve this?
Thank you in advance.
P.S: David's suggestion is right, this is a better way to create an editable DB:
- (void) createEditableDatabase{
BOOL success;
NSFileManager *fileManager = [NSFileManager defaultManager];
NSError *error;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:#"DB.sqlite"];
success = [fileManager fileExistsAtPath:writableDBPath];
if (success){
return;
}
NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:#"DB.sqlite"];
success = [fileManager copyItemAtPath:defaultDBPath toPath:writableDBPath error:&error];
if (!success) {
NSAssert1(0, #"Failed to create writable database file with message '%#'.", [error localizedDescription]);
}
}
P.S2: this could be an appropriate error checking, let me know if it's right or not.
int rc;
while ((rc = sqlite3_step(statement)) == SQLITE_ROW){
NSLog(#"ROW");
}
if (rc != SQLITE_DONE){
NSLog(#"%s: step error: %d: %s", __FUNCTION__, rc, sqlite3_errmsg(myAppSQLite));
}

Answer 1

You never actually execute the query by calling sqlite3_step.
You want:
if (sqlite3_prepare_v2(myAppSQLITE, query_stmt, -1, &statement, NULL) == SQLITE_OK){
sqlite3_step(statement); // add appropriate error checking
sqlite3_finalize(statement);
}